Dietary Supplementation with Bupleuri Radix Reduces Oxidative Stress Occurring during Growth by Regulating Rumen Microbes and Metabolites.

Simple Summary: Oxidative stress is closely related to animal health. Bupleuri Radix, a well-known Chinese herb, has an important antioxidant capacity. In this study, we discovered that supplementing Bupleuri Radix to the diet could reduce oxidative stress during the growth stage of Shanbei fine-wool sheep. In addition, we analyzed the antioxidant mechanism of Bupleuri Radix by combining metabolomics and microbiomics and discovered that Bupleuri Radix may increase the antioxidant capacity of Shanbei fine-wool sheep by regulating rumen bacteria and metabolites. The findings indicate that implementing appropriate nutrition strategies can improve the health of Shanbei fine-wool sheep. Oxidative stress (OS) in ruminants is closely associated with disease; thus, improving antioxidant capacity is an important strategy for maintaining host health. Bupleuri Radix (BR) could significantly improve host health and stress levels. However, the clear antioxidant mechanism of the function of BR remains unknown. In the current study, LC-MS metabolomics combined with 16S rRNA gene sequencing was employed to explore the effects of BR on rumen microbiota and metabolites in Shanbei Fine-Wool Sheep (SFWS), and Spearman correlation analyses of rumen microbiota, metabolites, and OS were performed to investigate the mechanism of antioxidant function of BR. Our results indicated that as SFWS grows, levels of OS and antioxidant capacity increase dramatically, but providing BR to SFWS enhances antioxidant capacity while decreasing OS. Rumen microbiota and OS are strongly correlated, with total antioxidant capacity (T-AOC) showing a significant negative correlation with Succiniclasticum and a positive correlation with Ruminococcus. Importantly, the Chao1 index was significantly negatively correlated with malondialdehyde (MDA) and positively correlated with superoxide dismutase (SOD) and T-AOC. Two biomarkers connected to the antioxidant effects of BR, 5,6-DHET and LPA (a-25:0/0:0), were screened according to the results of metabolomics and Spearman analysis of rumen contents, and a significant relationship between the concentration of rumen metabolites and OS was found. Five metabolic pathways, including glycerolipid, glutathione, nucleotide, D-amino acid, and inositol phosphate metabolism, may have a role in OS. The integrated results indicate that rumen microbiota and metabolites are strongly related to OS and that BR is responsible for reducing OS and improving antioxidant capacity in post-weaned SFWS. These findings provide new strategies to reduce OS occurring during SFWS growth. [ABSTRACT FROM AUTHOR]